Control apparatus



T. WHITEFORD March 7, 1939.

CONTROL APPARATUS Filed Oct. 8, 1937 2 Sheets-Sheet 1 c/rzaerz Wz J W W Q w y h W W 5 Q M 3 March 7, 1939. T. WHITEFORD CONTROL APPARATUS '2- Sheets-Sheet 2 Filed Oct. 8, 1937 Patented Mar. 7, 1939 UNITED STATS ATENT OFFICE 17 Claims.

This invention relates to control apparatus in general and particularly to that type of control apparatus for radio receiving sets known as automatic tuning apparatus, in which there is some v automatic means for stopping the movement of the tuning unit for the set at the point of accurate tuning for a predetermined station.

Automatic tuning has recently become very popular and is a great aid to the average person in providing a device for automatically stopping the tuning movement at the right point on a predetermined station setting. People who donot understand radio thoroughly have had great difiiculty in properly tuning a radio receiving set since they seem to be unable to find what may be called the position of peak tuning at which the receiving set is tuned to the exact frequency desired. Even experts have necessarily had to turn the tuning device past the position of peak tuning in order to be sure they had reached it, and then turn back to the peak. A variety of devices have therefore been devised for facilitating peak tuning, or at least facilitating tuning to a desired broadcast station frequency without requiring 5 the operator to closely Watch the radio dial or taxing'his memory to recall the particular frequncy of the station, and these are classed generallyas automatic tuning devices. The forms of automatic tuning which have been known heretofore have either lacked flexibility and accuracy or have required very expensive electrical or mechanical contrivances.

According to the present invention a very simple device has been originated which may provide absolute accuracy and is nevertheless extremely economical. In general, it includes a revolving threaded member and a spring pressed ball riding on the threads and cooperating with notches in the thread as a spring detent for stopping the tuning movement at the correct predetermined positions for providing peak tuning for the stations desired. The notches are formed accurately for each individual receiving set and for the particular stations desired by the individual owner by carefully tuning the set to each of these stations and then pressing the ball into the thread'with a suitable tool such as a pair of pliers. It is thus seen that the device is highly flexible since as few or as many stations may be logged on the thread as may be desired, and since additional stations can be added as the owner desires at any time.

The objects'of the invention are sufliciently evident from the foregoing, but in summary are to provide an economical automatic tuning device which is highly accurate and yet highly flexible in conforming to the desires of the owner.

Additional objects and advantages will be apparent from the following description and from the drawings, in which'i Fig. 1 is a perspective and partly diagrammatic View partially broken away, showing the general combination of this invention as used in an automobile receiving set.

Fig. 2 is a longitudinal sectional view through the automatic tuning unit seen in Fig. 1.

Fig. 3 i's'a vertical sectional View on the line 33 of Fig. 2. I

Fig. 4 is a view similar to Fig. 2 but showing a modified form of control cable.

' Fig. 5 is a horizontal sectional and somewhat diagrammatic view indicating a control unit embodying this invention as applied to a home receiving set.

Fig. 6 is a longitudinal sectional View through the automatic tuning knob of Fig. 5.

Fig. 7 is a vertical sectional view taken on the line 1- ofFig. 6.

Fig. 8 is a corresponding View taken on the line 8-8 of Fig. 6.

Although this invention may take various terms, only three forms have been chosen for illustration and in all of these the automatic tuning device itself is substantially the same. In all forms of the invention illustrated the tuning device is used in conjunction with tuning condensers Ill of a radio receiving set, though as an automatic control'device it might be used in many other connections.

In the forms of the invention shown in Figs. 1 to 4 the radio receiving set II is one especially suitable for automobile use, being controlled by a remotely positioned knob l2 on the instrument panel l3. The knob I2 is connected to the receiving set by a cable I 4 in a sheath [5. The automatic tuning unit "5 is interposed between the knob l2 and the condensers I0. In Fig. 4 the cable I4 extends through the unit I6, while in Fig. 2 the cable I4 extends into the unit I6 and a short connecting cable l4 connects the unit It with the condensers II]. In Fig. 2 the cables l4 and 14. each has at its end a connecting plug l8 which is square in cross section and which fits axially into a cylinder I9 which is correspondingly shaped on its inside so that the cylinder I9 is rotated by the cable It and in turn rotates the cable M to turn the condenser rotors. In Fig. 4.- a single plug i8 is soldered or otherwise secured to the cable 14 and keys the cylinder 19 to the cable to rotate therewith. It will be observed with both types of connections. Since these embodiments shown in Figs. 2 and 4 are alike except for the connecting cables, the description of these figures will be limited to the form shown in Fig. 2.

The cylinder I9 rotates within a fixed housing 2| which extends outwardly from a collar 22 secured to a support plate 23 in any suitable manner as by passing through the plate 23 and being upset thereon. The plate 23 is secured to the casing of the receiving set II.

The cylinder I9 is formed with threads 26 on its outer side, forming a thread channel 21. A steel ball 28 rides in this channel, being positioned within a slot 29 in the fixed housing 2 I, this slot extending longitudinally of the cylinder and the cable so that the ball can move longitudinally from end to end of the cylinder but cannot revolve around the cylinder. The ball 28 is resiliently pressed against the cylinder I9 by a spring clip 3I shown in the form of a split spring steel cylinder. The parts are held in proper relationship by virtue of an annular flange 32 on the end of the cylinder I 9 which holds the spring clip 3| in place and a spring retaining wire 33 sprung into a groove within the flange 32 which retains the cylinder I9 in place. A washer 34 is preferably provided between the retaining wire 33 and the cylinder I9.

' the several revolutions of the cable I4 the cylinder I9 likewise makes several revolutions, causing the ball 28 to ride approximately from one end of the slot 29 to the other, riding along the length of the channel 21 intervening its two positions. If at any point in this channel the ball 28 should strike an indentation or notch 36, it would act as a spring detent and tend to stop rotation of the cylinder I9 and hence stop the tuning movement. Since the indentations 36 are positioned, in a manner to be described, in proper positions for stopping the tuning movement to provide peak tuning for'particular stations, this spring detent action of the ball 28 provides automatic tuning. When the user wants to tune in on a particular station, he simply turns the knob I2 until the ball 28 springs into the notch 36 corresponding to the station desired. When the ball takes hold, the set is properly tuned and no hunting or movement of the knob back and forth is required. For the sake of accuracy theball 28 should move snugly in the slot 29 and of course the notches must fit the ball accurately.

Logging the stations With expensive automatic tuning devices of the past the automatic tuning of one station is independent of that of another and there is little objection to having automatic tuning facilities for a large number of stations. With the type of automatic tuning of the present invention, howa the notches separately on each individual set so that each owner can have just the notches he threads 26 of the cylinder.

that the same form of cylinder l9 may be used wants. The forming of the notches may be called logging the stations.

The initial notches will ordinarily be formed by the seller of the set after installing the set, though additional notches may very easily be made later by the set owner. To obtain access for forming the notches it is merely necessary to remove the cover AI. This may be done by loosening the set screw 42 and set screw 43 and sliding the cover AI outwardly along sheath I5.

Before forming the indentations the set must be properly and exactly tuned by turning the knob I2 to turn the cylinder I9.' When the set is satisfactorily tuned on a station to be logged, a pair.

of pliers is used to press the ball 28 downinto the cylinder I9, or, more exactly, down into the To this end it is of course desirable that the ball 28 be of hardened steel and that the cylinder I9 be formed of a metal which is considerably softer, as, for example, a brass alloy. The metal of the cylinder should be sufiiciently hard, however, so that it will be virtually impossible to press the ball as much as half of its diameter into the metal, since if the ball were pressed as far as half its diameter into the metal it would be impossible or too diflicult to dislodge the ball by turning the cylinder. To this end the depth and width of the channel 21 is preferably made such that a solid seat will be formed for the ball by deformation of the threads 26 before the ball is too deeply embedded. Although the ball may be pressed in quite easily at first, it cannot be pressed in without great difficulty after its seat is solid After one station has thus been logged by forming a notch therefor, the set will be tuned in to another desired station and another notch formed and this will be kept up until all of the stations which the user expects to want to listen to have been logged.

It will be observed that in forming the notches 36 it is not necessary to remove the spring clip 3| 7 in order to press the ball 28 into the threads with pliers since the pliers may act through the clip 3|, the clip either spreading enough to permit the pliers to contact the ball 28 through the split of the clip or else transmitting the thrust from the pliers to the ball. The edges of the clip at the split therein are preferably bevelled as seen in Fig. 3 so as to engage the ball more satisfactorily. If desired, the clip may be made to serve as an absolute safeguard against pressing the ball too far into the cylinder I9 by so proportioning the parts that the portions of the clip 3I adjacent the split therein will come to rest on the fixed housing 2| and prevent further movement of the pliers before the ball 28 has been pressed too far into the cylinder I9.

In order that the ball 28 may be pressed into the cylinder with sufiicient ease even though the cylinder is made of a metal hard enough to prevent the ball from being pressed too far, the threads 26 are sufficiently narrow so that they will be bulged outwardly as the ball is pressed in. In order that the outward bulge will not be felt as the ball passes along the outside of the bulge the threads 26 are formed as double threads, or, in other words, there are two threads in parallel from one end of the cylinder I9 to the other. The result is that besides the channel 21 there is an'idle channel 45 which the ball 28 never engages. As a matter of fact, the bulges into the idle channel 45 are not ordinarily very noticeable, and if the user wishes to change his do so simply by shifting the ball 28 to the foraiicgoe merly idle channel. A person doing considerable traveling could have both channels, logged, one for one city and the other for another, and shift the ball from one channel to the other as occasion arose. Of course, there could be more than two channels on the cylinder if preferred.

The ordinary user will not very often use more than about six stations and hence will not have more than this number of stations logged with the notches already described. With such a small number of notches it will be very easy for him to keep in mind their relative positions and hence it will be quite convenient for him to tune in a given station without ever taking his eyes off of the road to look at the dial. Generally he will know what station the set is already tuned on and he can therefore simply turn the knob l2 a certain number of notches to the right or left. As soon as the ball falls into the desired notch the desired station will be properly tuned in. If the user does not know what station is already tuned in, a quick glance at the dial will tell him or he may turn the knob I2 in one direction to the end of the tuning range'and count the notches back to the station desired. It will be understood of course that counting the notches will be very easy since every time the ball 28 fallsinto a notch some effort will be necessary to dislodge it, or, in other words, the notch can be readily felt. As a matter of fact, there will also be an audible click, although in automotive radios the audible click will probably not be as important as the feel. Before the desired notch is reached, the knob l2 will be turned firmly so that the tuning movement will not stop when the ball 28 falls into an undesired notch 35, although the notch will be very distinctly felt. As the notch desired is approached, the user may loosen his grip on the knob I2 or turn it more gently and the tuning movement will automatically be stopped by the ball 28 falling into the notch 36, or the knob may be turned gently over its entire path of rotation, and additional turning pressure exerted to carry the ball through an undesired notch. 1

Some users will wish to have a few stations logged with the relatively deep notches already described and a few additional stations logged by very light notches sothat on the rare occasions when these additional stations are desired they can readily be found by the sense of touch alone. Of course, the set can be tuned in to any station by observing the dial. If desired, a user can have all of his notches of slightly varying depth, in which case his sense of touch will soon be developed enough to enable him to identify each station to which the set is tuned by the feel of the notch.

Changing the cylinder On rare occasions it will be desirable to change the cylinder I9 so as to permit a different station logging than that already on the original cylinder l9. This may occur when a station changes its frequency or goes off the air permanently, when the receiving set is sold to a different owner who prefers different stations, when the owner moves to a different part of the country, or as a result of changes in the set known as drifting. According to the present invention the cylinder may be changed very easily by simply removing the spring retaining wire 33, pulling the cylinder out and slipping a new cylinder in its place. Such replacement cylinders may be provided at a negligible cost.

HQme set It will be observed in Fig. 1 that the automatic tuning unit i6 is secured to the case of the set H rather than being positioned on the instrument panel. I3. This is necessary in order to secure accurate automatic tuning since the play or backlash in the cable It must not appear between the automatic tuner l6 and the tuning condensers It. In the case of a home radio receiving set, however, there is ordinarily no remote control of the nature shown in Fig. 1 and hence the automatic tuning unit may be positioned at the knob.

In Fig. 5 such a home set has been illustrated as including the condensers ii] driven through suitable reduction gearing through shaft 5| which is mounted in any suitable bearing and is turned by knob 52. The knob 52, though of a special shape, may be aesthetically balanced by matching it with an additional knob 53, serving some other purpose, such as for volume control. The knob 52 is in reality a hollow shell as seen in Fig. 6, serving not only as a control knob but also as a cover similar to the cover 4! in Fig. 2. The knob or cover 52 may be conveniently secured in place by a spring plug 54 secured to the knob 52 in any suitable manner as by means of the button 56. The spring plug 54 is preferably formed of a ribbon doubled to form a square plug fitting the hole in the center of the cylinder l9, as seen in Fig. 8. In this manner the spring plug 54 serves both to hold the cap or knob 52 onto the automatic tuning unit and to turn the cylinder as the knob 52 is turned. The shaft 5|, having a square plug at its end, fits into the other end of the cylinder l9 and hence is also turned by the knob.

The construction of the tuning unit shown in.

Figs. 5 to 8 is otherwise the same as that shown in Figs. 1 to 4 and therefore need not be described in detail. It includes the same cylinder l9, ball 28 and spring clip 3!. The collar 22 may be mounted directly on the bracket El secured on the chassis or condenser frame and may project substantially through an oversized hole in the cabinet 58.

The receiving set will of course include suitable indicating means driven by a suitable belt or gears 6!. The indicating'means may include a customary vane or pointer 82 positioned in front of a calibrated dial 63 and may also desirably include a rotating dial 64 having the names or call letters of the stations thereon so arranged that the call letters of whatever station is tuned in will be visible through a suitable opening 65 in the stationary dial 63. It will thus be possible to turn the knob 52 until it is stopped by virtue of the ball 28 falling into a notch 36 and then look at the opening 65 to see what station is tuned in. The pointer 62 may be used for tuning to a given frequency when the frequency of the station is known or for advising the user when he is approaching the desired station. With home sets where there is no objection to watching the indicating means it may be desired to have more notches 36 than with an automobile receiving set and it may also be desirable that these notches be not quite so deep since there will be an audible click to aid the sense of touch in informing the user when he has reached accurate peak tuning.

From the foregoing it is evident that an extremely inexpensive automatic tuning device has been provided which is extremely accurate and is also extremely flexible as to the automatic tuning facilities provided in accordance with the desires of each individual owner. Furthermore, the automatic tuning provisions may be completely changed with negligible expense. Also, the device is adaptable for both home and automobile receiving sets and is thoroughly satisfactory in each use. One of the important features in providing the flexibility of use already mentioned is the provision of means whereby the notches may be formed in a soft metal for each individual set according to the wishes of theowner. This feature can of course be obtained by a wide variety of devices, some of which may be very different from the threaded cylinder illustrated.

The disclosures of this application are illustrative and the invention is not'to be limited by them. In fact, if modifications or improvements are not at once obvious, they may be devised in the course of time to make additional use of the broad ideas taught and covered by this application. The claims are intended to point out novel features and not to limit the invention except as may be required by prior art.

I claim:

1. The combination of a radio receiving set including a tuning unit and a tuning control device therefor including a cylinder rotating with the movement of the tuning unit and having threads formed thereon of relatively soft metal, and a ball riding on and resiliently urged against the threads and restricted to movement longitudinally of the cylinder and resiliently urged against the threads whereby a notch in the threads will tend to cause movement of the cyl- ,inder to stop, the ball being harder than the threads and being accessible to the application of manual pressure whereby a notch may be formed by such manual pressure after the set has once been tuned to a station and, will thereafter aid in tuning the set to the same station.

2. A control device including a ball guide and a cylinder relatively rotatable, and a ball, the ball guide extending longitudinally of the cylinder and confining the ball to longitudinal movement therein, and the cylinder being threaded and engaging the ball whereby the ball rides along the threads in response to the relative rotation of the relatively rotating parts, the threads having notches therein and the ball being resiliently urged against the threads whereby at a predetermined point in the relative rotation the ball will fall into a notch and resist further relative rotation.

3. A control device including a ball guide and a cylinder relatively rotatable, and a ball, the ball guide extending longitudinally of the cylinder and confining the ball to longitudinal movement therein, and the cylinder being threaded and engaging the ball whereby the ball rides along the threads in response to the relative rotation of the relatively rotating parts, the threads having notches therein and the ball being resiliently urged against the threads whereby at a predetermined point in the relative rotation the ball will fall into a notch and resist further relative rotation, the cylinder being sufficiently soft and the ball being sufiioiently hard to permit formation of additional notches in the threads by a special force exerted on the ball whereby new stopping points may readily be formed.

4. A control device including a fixed cylindrical housing having a slot therein, a threaded cylinder within the housing adapted to engage a control element in keyed engagement therewith, a ball positioned in the slot and riding-on the threads, a split cylindrical spring clip surrounding the fixed cylinder and pressing the ball against the threaded'cylinder whereby notches which may be formed in the threads will tend to prevent relative rotation of the threaded cylinder and the fixed cylinder. 7 a

5. A control device including a fixed cylindrical housing having a slot therein, a threaded cylinder within the housing adapted to engage a control element in keyed engagement therewith, a ball positioned in the slot and riding on the threads, a split cylindrical spring clip surrounding the fixed cylinder. and pressing the ball against the threaded cylinder whereby notches in the threads will tend to prevent relative rotation of the threaded cylinder and the fixed cylinder, said threaded cylinder including a double thread whereby notches may be pressed into one thread channel, in which the ball rides, with attendant deformation of the threads into the idle channel.

6. A control device including a fixed cylindrical housing having a slot therein, a threaded cylinder within the housing adapted to' engage a control element in keyed engagement therewith, a ball positioned in the slot and riding on the threads, a split cylindrical spring clip surrounding the fixed cylinder and pressing the ball against the threaded cylinder whereby notches which may be formed in the threads will tend to prevent relative rotation of the threaded cylinder and the fixed cylinden the threaded cylinder being readily removable from the fixed cylinder for replacement by a. different threaded cylinder.

7. A control device including a fixed cylindrical housing having a slot therein, a threaded cylinder within the housing adapted to engage a control element in keyed engagement therewith, a ball positioned in the slot and riding on the threads, a split cylindrical spring clip surrounding the fixed cylinder and pressing the ball against the threaded cylinder whereby notches which may be formed in the threads will tend to prevent relative rotation of the threaded cylinder and the fixed cylinder, the fixed cylinder having a flange at each end for retaining the clip in place.

8. A control device including a fixed cylindrical housing having a slot therein, a threaded cylinder within the housing adapted to engage a control element in keyed engagement therewith, a ball positioned in the slot and riding on the threads, a split cylindrical spring clip surrounding the fixed cylinder and pressing the ball against the threaded cylinder whereby notches which may be formed in the threads will tend to prevent relative rotation of the threaded cylinder and the fixed cylinder, the spring clip being positioned with its split in engagement with the ball whereby the position of the ball is visible and rotative movement of the spring clip is prevented.

9. A control device including first and second relatively rotatable elements and'a detent carried by the first element and resiliently urged against 7 the second element whereby a notch in the second element will cause the detent to tend to stop relative rotation between the elements; the second element being sufficiently soft and the detent being sufliciently hard so that a special force applied to the detent will form a notch in the second element for providing a new automatic stopping position in the relative rotation of the elements.

10. A control device including first and second relatively rotatable elements and a detent carried by the first element and resiliently urged against the second element whereby a notch in the second element will cause the detent to tend to stop relative rotation between the elements; the second element being sufiiciently soft and the detent being suificiently hard so that a special force applied to the detent will form a notch in the second element for providing a new automatic stopping position in the relative rotation of the elements, the detent being at times accessible for manual application of such a special force through it to the second element.

11. A control device including first and second relatively rotatable elements, a detent carried by the first element and resiliently urged against the second element whereby a notchin the second element will cause the detent to tend to stop relative rotation between the elements, the second element being sufiiciently soft and the detent being sufiiciently hard so that a special force applied to the detent will form a notch in the second element for providing a new automatic stopping position in the relative rotation of the elements, means for connecting one of the elements to a manual operating device and to a radio tuning unit, and means for securing the other of the elements in a fixed position.

12. A control device including first and second relatively rotatable elements, a detent carried by the first element and resiliently urged against the second element whereby a notch in the second element will cause the detent to tend to stop relative rotation between the elements; the second element being sufficiently soft and the detent being sufficiently hard so that a special force applied to the detent will form a notch in the second element for providing a new automatic stopping position in the relative rotation of the elements, the detent being at times accessible for manual application of such a special force through it to the second element, and a cover for the device to render the detent inaccessible and forming a knob by which one of the rotative elements may be turned.

13. A radio receiving set including support means, a tuning unit mounted thereon, a tuning control device including a fixed housing carried by the support means, and having a slot therein, a threaded cylinder within the housing connected to the tuning unit for turning therewith, a ball positioned in the slot and riding on the threads, resilient means pressing the ball against the threaded cylinder whereby notches in the vthreads will tend to prevent relative rotation of the threaded cylinder and the fixed cylinder, and a cap removably secured to the threaded cylinder, enclosing the fixed housing and forming a knob for turning the cylinder and tuning means; the cylinder being sufficientlysoft and the ball sufficiently hard so that when the cap is removed the ball may be pressed into the cylinder by manual pressure to form a notch in the threads.

14. A radio receiving set including support means, a tuning unit mounted thereon, a tuning control device including a fixed housing carried by the support means, and having a slot therein, a threaded cylinder within the housing connected to the tuning unit for turning therewith, a ball positioned in the slot and riding on the threads, resilient means pressing the ball against the threaded cylinder whereby notches in the threads will tend to prevent relative rotation of the threaded cylinder and the fixed cylinder, and a cap removably enclosing the fixed housing; the cylinder being sufiiciently soft and the ball sufficiently hard so that when the cap is removed the ball may be pressed into the cylinder by manual pressure to form a notch in the threads.

15. A control device for controllable apparatus including a pair of adjacent elements, one of said elements being rotatable with respect to the other, a continuous spiral channel on one of said elements, a detent riding in said channel, means including the other of said elements for maintaining said detent in said channel. and means for impeding the movement of said detent at predetermined points in said channel.

16.A control device for controllable apparatus including a fixed element and a rotatable element with said elements being separable with respect to one another, one of said elements having a continuous thread thereon and the other of said elements having an elongated slot therein, a detent in said slot riding on said thread, means for impeding the movement of said detent at a predetermined point in said thread, and means for urging said detent onto said thread.

17. The combination of a radio receiving set including a tuning unit, a control knob remote therefrom, and a tuning control device including a fixed element, a rotatable element con nected to operate the tuning unit by rotating through more than one revolution during the tuning of the unit, associated so directly with the tuning unit as to eliminate play therebetween, and connected to be rotated by the control knob; one of said elements having a continuous thread and the other of said elements having an elongated slot therein, a detent in said slot riding on said thread. and means for urging said detent onto said thread, said threaded element having formations adapted to co-act with the detent at a plurality of points during the rotation of the movable element to impede movement of the movable element and hence assist in the accurate tuning of the tuning unit in spite of any variability between the movable element and the control knob.

THOMAS WHITEFORD. 

